[Brando]

I'm sorry to hear about your friend, my condolences.

I have heard countless stories about HD's "Death Wobble". Some say it has to do with the shift of weight from front to rear during deceleration or braking, something hits the front suspension just right and sets it off. Others say it's and issue with the suspension design of the rear swing-arm and sometimes bad motor mounts. The common thread is speed above 80mph.

Here's a short clip of how it goes, excess of 100mph:


Another at about 120mph:


Finally another showing the rear swing arm bushing issue: